Metabolism of ochratoxin A by primary cultures of rat hepatocytes

Abstract

Association of ochratoxin A with cultured rat hepatocytes occurred at 4.degree. C and the saturation level in the medium was 0.3 mM ochratoxin A, with maximal binding after 60 min. At 37.degree. C, the level of cell-associated ochratoxin A increased up to 6 h and remained at 2 nmol toxin/mg cell protein for 30 h. With increasing concentrations of ochratoxin A, increasing amounts of the toxin accumulated in the cells; saturation occurred at 0.3 mM. Ochratoxin A was metabolized by hepatocytes at 37.degree. C. (4R)-4-Hydroxyochratoxin A appeared in the medium at a maximal level (.apprx. 30 nmol/mg cell protein) at an ochratoxin A concentration of 0.25 mM after 48 h incubation. Small amounts of (4S)-4-hydroxyochratoxin A were detected only after incubation for .gtoreq. 22 h.